In renewable and electric power system applications, a three-phase grid-connected DC/AC voltage-source pulse-width modulation (“PWM”) converter can be employed at the interface between the DC and AC systems. Referring now to FIG. 1, a block diagram illustrating grid-connected converters (“GCC”) used in a micro-grid to connect distributed energy resources is shown. Typical converter configurations containing the GCCs include: 1) a dc/dc/ac converter 102 for solar, battery and fuel cell applications, 2) a dc/ac converter 104 for static synchronous compensator (“STATCOM”) applications, and 3) an ac/dc/ac converter 106 for wind power and HVDC applications. Conventionally, these types of converters are controlled using standard decoupled d-q vector control techniques.
Notwithstanding its merits, recent studies indicate that the conventional vector control strategy is inherently limited, particularly when facing uncertainties. For instance, it has been shown that wind farms periodically experience a high degree of imbalance and harmonic distortions, which have resulted in numerous trips. Additionally, tuning proportional-integral (“PI”) controller parameters for the standard control techniques in STATCOM applications is difficult. Accordingly, significant challenges have been identified in the development of microgrids based on conventional vector control technologies.